3.23 Multi-headed Engines

multihead, -M

This switch makes it possible to add extra engines to a train. This can be
especially useful in the early game, or in mountainous terrain. The extra engines
increase the total power available to accelerate the train, but of course they
also add weight. This means that extra engines only make sense if they weigh
much less than the total weight of the train, otherwise they are a waste of money.

Another small benefit of additional engines is that they increase the
maximum speed slightly, because there is some excess power available to accelerate the train to a higher speed. The first additional engine adds 20%, the next one
10%, and a third extra engines add another 5%. After that adding more engines will not
increase the speed any more. The amount of this increase (in percent) is an option
to the switch, the default is 35% in total. If you want the game to be more realistic,
you should probably disable the speed increase using multihead 0. Otherwise,
the parameter can be anything between 0 and 100, in which case the additional
engines add 4/7, 2/7 and 1/7 of that amount, respectively.

Now the big question is, how do you buy these additional engines?
Here, the answer is once more the magic Ctrl key. Simply open a depot with
a train in it, and select the engine to buy. Now, before you click on the
"Purchase" button, hold down the Ctrl key, then click the button. This
creates a new engine that behaves sort of like a carriage, in that you can place
it anywhere on the train. If you have the train info window open, you can see
how the train power and speed changes if you add or remove engines.

A slight complication arises for the engines that normally come with two heads, like
the Asiastar for example. In this case, when you buy an engine, you'll only buy a
single one and not both. Then, using the Ctrl key, you can buy a second or
even a
third engine. Note that the maximum speed given in the purchase window is the one
for a dual-engine train. This means that if you only buy one engine of the Asiastar,
it will actually be slower than what is stated in the window. Only
adding a second Asiastar engine will raise the maximum speed to the normal value.

The Ctrl key also has another function. It selects
which way an engine faces. If you move an engine around in the depot while holding
down Ctrl, it will face one way. If you move it without holding Ctrl, it
will face the other way.

In multiplayer games, the Ctrl key doesn't work. Here, you buy additional
heads if there is already an engine in the depot. This means that the first
engine you buy is a regular one, all other engines are additional heads. You
can therefore only have one train in a depot when buying engines, and to buy
a new train, you must not have another train in the depot..